In the modern world, with the increase of hustle and bustle and travel, there is a demand for reducing the time and labor involved in laundering and/or fabric care chores. That is, consumers desire a product that delivers not only excellence in cleaning, but also superior fabric care or garment care benefits, for example: superior garment appearance; excellent tactile characteristics, such as fabric feel and softness; fabric softness; reduction, removal or prevention of creases or wrinkles in garments; ease of ironing; garment shape retention and/or shape recovery; and fabric elasticity. Compositions that provide both cleaning and fabric care benefits are commonly known as “2-in-1 detergent compositions”.
Fabric care benefit agents need to be deposited onto fabrics in order to provide the desired benefits. However, the deposition efficiency of the fabric care benefit agents under common laundering conditions is low. Most of the fabric care benefit agents remain in the wash liquor and are discarded with the wash liquor.
In order to increase the deposition of fabric care agents, deposition aids are often used. Deposition aids (for example, cationic deposition polymers) suitable for enhancing the deposition of fabric care benefit agents have been added to the laundry detergent compositions. Suitable deposition aids preferably do not interfere with the cleaning operation which removes substances from the fabrics, and at the same time, enhance the deposition of fabric care benefit agents onto the fabrics. In addition, suitable deposition aids preferably are compatible with the cleaning agents, detergent additives and/or fabric care agents in the composition and remain stable in the compositions.
The most commonly used deposition aids are cationic polysaccharides. U.S. Pat. Nos. 7,056,880 and 7,056,879 (both assigned to The Procter & Gamble Company, “P&G”) disclose compositions employing cationic hydroxyethyl cellulose derivatives as deposition aids to increase the deposition of fabric care agents. Cationic guar gums and synthetic polymers for assisting and/or enhancing the deposition of silicones on fabrics are disclosed in WO 04/041983. However, the natural polysaccharide-based polymers are not compatible with detersive enzymes, particularly cellulases, amylases and mannanases. These enzymes are either purposefully incorporated in laundry detergents to increase cleaning and removal of pill and fuzz, or are present as impurities in other enzymes, for example, commercially available proteases and amylases contain a trace amount of cellulase. These enzymes break down polysaccharide-based polymers during the laundering operation in the washing machine, or during shipping and storage of the liquid detergents, thereby shortening the shelf life of the liquid detergents.
One way to circumvent this problem is to use a synthetic cationic polymer. A variety of synthetic cationic polymers are available. These polymers are listed in International Cosmetics Ingredient Dictionary and Handbook, 10th Edition, published by The Cosmetics, Toiletry and Fragrance Association, Washington D.C. However, most of these commercially available cationic polymers are not compatible with laundry detergents containing anionic surfactants. It is believed that the cationic polymers interact strongly with anionic surfactants which lead to precipitation of the anion-cation complex. There are significant challenges to formulate liquid laundry products from these components.
Various combinations of cationic polymers, cross-linked silicones with free silanol groups and anionic surfactants are known. However, many of the cationic polymers do not formulate well to produce clear isotropic liquid detergent products. This is particularly observed when the cationic polymers are variations of polyquaternium-7. Polyquaternium 7 typically is produced by a monomer feed ratio of 70% acrylamide and 30% diallyldialkylammonium chloride (DADMAC). When the resulting copolymers are incorporated in liquid laundry detergent, they produce two-phased opaque products. Without being bound by theory, this is believed to be due to a large amount of unreacted DADMAC monomer and poly(DADMAC) oligomers that interact and precipitate with anionic surfactants, such as alkyl sulfates and alkyl ethoxysulfates, in the detergent composition. See, for example, WO 2005/097907.
Hence, there remains a need for improving fabric care benefits provided by laundry detergent compositions. In particular, there remains a need to select fabric care agent, deposition aid and cleaning agent that are compatible so that the resulting detergent composition is stable, deposits the fabric care agent efficiently, and provides superior cleaning and fabric care benefits.